Laminating device for joining a metal strip and an insulating material strip

ABSTRACT

Apparatus for bonding an insulating material to a metal strip having a conveyor for moving a strip of insulting material along a path of travel and a mechanism for placing perforations in the strip and cutting the strip into sections of predetermined length. The conveyor has raised registration studs that pass through the perforations. A metal strip that also contains perforations is brought into moving contact with the section with its perforation being registered on said studs and a heat curable bonding material is introduced between the metal strip and the insulation sections. A second conveyor is then moved into pressure contact with the moving sections and metal strip registered on the first conveyor and heat is applied to cure the bonding material.

BACKGROUND OF THE INVENTION

The invention described herein relates to a device for bonding twodifferent materials. Applications include chip card manufacturing and,more precisely, the manufacture of the chip base such chip cardscontain.

Chip card use is on the increase, notably in the digital payment fieldwith bank and phone cards.

It is common knowledge that a chip card consists of a stiff plastic cardwith a hole, generally located in one of its corners. The hole receivesan assembly of a base and an electronic component, commonly called a"chip". The chip base itself is usually made of two component parts,viz. a perforated metal part called a grid and an insulating part. Thegrid acts as a connecting interface with the chip. The grid is dividedin separate areas or connectors, each designed to enter into contactwith a pin of the machine the card is inserted in. The opposite side ofthe grid is covered with an insulating film with a certain number ofperforations. Each perforation is precisely positioned on an area of thegrid. It is thus possible to connect each grid connector with an area ofthe chip using metal but usually gold wire.

To automate the manufacturing process, highly precise positioning isrequired to match the perforations in the insulating layer to the metalgrid.

As a rule, grids are produced on long strips onto which the insulatinglayer, a strip of equivalent width, is hot-bonded. Unfortunately, asmaterials differ, grid and perforation intervals are not rigorously thesame. This precludes the manufacture of very long strips, unlesspatterns are realigned.

The problem quite clearly stands in the way of automatically producingvery long strips.

In an attempt to solve the problem, a complex machine has been proposedthat operates on the following principle. On a uniform length of metalstrip on which grids are located at given intervals, an insulating stripwith perforations located at slightly narrower intervals is placed. Theinsulating film is stretched over the uniform length of metal strip insuch a manner as to match the perforations in the insulating strip withthose constituting the grids. Stretch is controlled by a match-detectingcamera system. When perfectly positioned, the insulating layer isapplied and bonded to the metal strip. Though producing satisfactoryresults, the device, operating in a sequential manner, is not suited formass production.

This state of the art may be illustrated by the contents of patentsGB-A-2 031 796 and WO-A-92 15118.

To solve the problem of matching the insulating strip perforations tothose in the metal strip, a solution has been proposed in conformancewith patent EP-A-0 296 511. The patent describes a device in whichperforated sheets of insulating material are placed on and bonded to ametal strip in a manner that matches the perforations in the insulatingmaterial to those in the metal strip. According to the device disclosedin the patent, each sheet is placed on and subsequently bonded to themetal strip with no micro-alignment between the positioning and bondingoperations.

The problem the invention aims to solve, therefore, is that of making abonding device that will attach a metal strip with periodic perforationsto a strip of insulating material with perforations spaced at likeintervals. To solve the problem, a device has been conceived anddeveloped comprising:

a system to perforate the insulating strip at regular intervals on theone hand and cut said insulating strip in sections, on the other;

a system to position the metal strip onto said sections of insulatingstrip and a system to convey the metal strip positioned onto saidsections of insulating strip;

a system to micro-align each section relative to the metal strip ontowhich the section has been placed to match the perforations of eachstrip with great precision;

a system for bonding each section of insulating strip to the metalstrip.

Given this combination of systems, it is clear that the devicesimultaneously moves the metal strip and positions each section relativeto said strip to rigorously match the perforations. As centring andconveying operations are concomitant, bonding is a continuous processrequiring neither stopping nor adjustment sequence.

SUMMARY OF THE INVENTION

To solve the problem of conveying the sections of insulating film, thesystem cutting the insulating strip in sections consists of:

a system for precutting the sections;

a system for affixing at least one length of adhesive tape as a functionof strip length at least onto the precut areas;

a system for severing the areas not precut to obtain separate sections,temporarily linked by at least one length of adhesive tape.

The film, therefore, is cut into a number of sections which aresubsequently linked by adhesive tape to form a continuous series ofsections easy to convey.

The cutting device is separated from the bonding device proper.

To solve the conveying problem, a positioning and conveying system ismade up of a chain of mutually articulated links wide enough to receivethe insulating and the metal strips, each link being slightly longerthan the section of insulating strip and equipped with feed studs.

Each film section is carried along by a single link.

To solve the important problem of matching the perforations of eachsection to those of the metal strip, the system used to performmicro-alignments of each section in relation to the metal strip consistsof:

a main platform designed to carry cutout sections acting as the top ofeach link;

a plate within the link body, set back from the platform and movableparallel with the length of the strip and equipped with feed studs, saidstuds protruding through the holes of a greater diameter in theplatform.

It clearly appears that the feed studs are integral with a plate thatcan move in relation to the drive chain. Thus, as each section is movedalong by the plate when the studs convey the metal strip, the section isautomatically and mechanically centered onto the matching part of themetal strip.

Advantageously, and so as to make conveying strips of differingcharacteristics possible, notably as regards the position of the feedholes, the platform and the movable plate are a removable chain linksub-assembly.

As regards the assembly of the film and the metal strip, the systemnotably uses induction heating to bond the two superposed strips.

Advantageously, the bonding system includes:

a chain of press plates moved along at the same speed as the conveyingchain, each of the press plates having the same dimensions as theplatforms it faces and touches;

two sets of inductors facing each other, the lower set being locatedslightly below the trajectory of the conveyor platforms and the upperset being located slightly above the trajectory of the press plates, insuch a manner that energizing the inductors will set up a current acrossthe facing metal plate.

To solve the problem of local hot spots causing irregular bonding, eachpress plate has a metal area designed to face the metal strip anddiffuse the heat, rendering the temperature of the surface to be bondeduniform.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present invention may be more readily understood, thefollowing drawings are provided, viz.,

FIG. 1, a schematic drawing of the invention,

FIGS. 2 and 3, top views of respectively the insulating and the metalstrip before bonding,

FIG. 4, a schematic drawing of insulating strip cutting station, while

FIG. 5 shows its progress through the cutting process,

FIG. 6, a schematic drawing of the chain conveying the two strips, while

FIG. 7 shows its evolution in each stage,

FIG. 8, a cross section of a conveyor chain link.

DESCRIPTION OF THE INVENTION

As stated, the device is advantageously applied for bonding a metalstrip to a strip of insulating material.

The metal strip (2) as illustrated in FIG. 3, generally of copper orbronze, is approximately 35 millimeters wide. It has two rows ofidentical patterns (2.a) used to form the grids. It goes without sayingthat the variety of patterns is wide (square, round, etc.), as are thecutout shapes that are determined by the function the card is to fulfil.As a rule, patterns have 8 cutout areas (2.b) located at uniformdistances from each other (the distance between each double patternbeing the pitch).

The insulating film (3) comes in the shape of a strip of the same width(see FIG. 2). It is made of polyimide, a product sold under the Kapton®brand by Du Pont de Nemours corporation. It has two rows of groups (3.a)of perforations (3.b) patterned to match the grid areas (2.a) of themetal strip (2). One of the sides of this strip receives a layer ofhot-melt glue. This layer of glue is covered with a polyester protectivefoil (3.h) as commercially available from the same supplier under theMylar® brand.

The two strips feature the same perforations (2.c, 3.c) for feed-throughand centring. As regards their positional variation, it is consideredthat the insulating strip has a tolerance of two hundredths of amillimeter over an 8-pitch equivalent length as the punching tool isdesigned to operate on 8 pitches simultaneously, whereas the metal striphas the same tolerance but in cumulated pitches.

The machine shown in FIG. 1 consists of two wholly separatesub-assemblies, viz., a cutout station (4) and a conveyor/bonding chain(5).

The cutout station (4), shown in FIG. 4, is in order of filmfeed-through equipped with a feed-out unit (4.a) unwinding anddispensing a roll of insulating film covered by protective foil, apunching tool (4.b) to perforate and precut the Kapton, a feed-out unit(4.c) of adhesive tape and a pressure roller (4.d) and a tape cutter(4.e) to sever precut sections.

As can be seen from FIG. 5, the punching tool (4.b) in addition toperforating the Kapton, punches two lines (3d) across the insulatingstrip. Sections are held together at only three points, viz. the middle(3.f), the beginning and the end of the cross-cut (3.e). Cross-cutsseparate 8-pitch units (7).

The punching tool perforating and precutting the strip is followed bythe taping station (4.c, 4.d) which affixes two lengths of adhesive tape(6) to the center of the cross-cut (3.d) without covering thefeed-through holes (3.c) or the parts not precut (3.e, 3.f).

And lastly, cutout is completed by a final severing operation (4.e).This is performed by a cutter (4.e.1) with three knives located over thecentral (3.f) and end (3.e) parts of the strip. It goes without sayingthat final cutout width is controlled to prevent damage to the lengthsof adhesive tape (6).

To sum up, the cutout station feeds out a succession of single sections(7) held together by two lengths of adhesive tape (6). The strip,therefore, is a compound one that can be conveyed.

FIG. 6 shows one of the invention's principal characteristics, i.e., thecombined conveying and centring system. The system is based on a chain(8) of articulated links. It is driven by a crown wheel (9). Each link(8.a) in addition to rolling gear (8.a.1) has a main platform (8.a.2),which receives the insulating strip (3). This platform has at least 4holes (8.a.3). Four feed studs (8.a.4) protrude up through these holes.These four studs are integral with a movable plate (8.a.5) set back fromthe platform (8.a.2). This plate can move in a parallel plane with theplatform.

As can be seen from FIG. 6, the first links (8.a, 8.b) of the chain movethe insulating strip (3) forward. Strip tension causes the movableplates (8.a.5, 8.b.5) to be pulled back to their home position at therear of the feed stud holes (8.a.3, 8.b.3). Due to the adhesive tape(6), the next section can be pulled through.

As indicated, the insulating strip is covered by a film (3.h) protectingthe glue. Prior to removing the metal strip, the Mylar® film and thelengths of adhesive tape (6) are separated and wound for future use.From that moment on, the section under consideration (7) is free andsubject to no drive strain.

When the next link (8.c) presents itself, the metal strip is placed overthe link carrying an insulating section. The feed studs (8.c.4),traversing the metal strip through the appropriate holes (2.c), move themetal strip (2) along. As a consequence, the movable plate (8.c.5) movesin such a manner that the feed studs (8.c.4) align the feed holes (2.c)in the metal strip with those (3.c) of the section concerned.

As can be seen from FIG. 6, the movable plate (8.c.5) moves forward inrelation to its matching link (8.c). Perforations are thus perfectlymatched across 8-pitch sections. At the end of this stage, each link(8.d) carries a part of the metal strip on top of a perfectly positionedsection of insulating film.

Bonding proper takes place somewhat later. The operation requires asecond chain (10), called the press chain. It consists of links (10.a,10.b) of the same size as the conveyor links. It is designed to apply acertain pressure to the strips during heating.

The heating system consists of two inductor sets (11.a, 11.b) located asnear to the platforms (8.a.2, 10.a.1) as possible. As can be seen fromFIG. 8, the links are shaped as an up-ended U-channel with the platform(8.a.2) as its base and the rolling gear (8.a.1) as its legs. Theinductors (11.a) penetrate the inter-leg space and face the platform(8.a.2).

The links of the upper chain are made up of a press plate (10.a.1) usedto press the metal strip to the insulating section. The part of thepress plate in contact with the metal strip is an integral metal pad(10.a.2).

Energizing the inductors (11.a, 11.b) causes eddy currents to flow inthe metal strip (2) and produce heat. The consecutive temperature risecauses the layer of glue on the insulating film (3) to melt, bonding thetwo strips. As a result of the cutouts (2.b) in the metal strip,currents induced are poorly distributed. This is why a metal pad(10.a.2) is applied: acting as a diffuser, it equalizes the temperature,ensuring uniform bonding.

The preceding description concerns only one particular embodiment of theinvention. The use of similar means would still be covered by the sameinvention. The use of cutting tools mechanically linked to drivemechanisms or used wholly separately would be a case in point.

It results from the above that the device according to the invention,contrary to existing systems, combines high precision in manufacturingbonded strips with the continuous operation of manufacturing lines.

What is claimed is:
 1. A machine for continuously and automaticallybonding a metal strip to an insulating material, said machinecomprising:a metal strip having longitudinally spaced apart perforationsand aligning holes formed therein; a conveyor means for continuouslymoving a strip of insulating material along a linear path of travel;perforating means positioned along said path of travel for continuouslyforming perforations and aligning holes in said insulating strip thatare in the same alignment as the perforations and aligning holes formedin said metal strip; cut-off means for cutting the insulating strip intosections as the strip continuously moves along said path of travel, eachsection containing at least two aligning holes; registration meansmounted upon said conveyor containing pins that are capable of passingthrough said aligning holes contained in said sections; positioningmeans for moving said metal strip into registration with said sectionsso that said pins are further passed through the aligning holes in saidmetal strip whereby the perforations in said metal strip are located inregistration with the perforations in said insulation sections; andbonding means for attaching the insulation sections to the metal stripwhile the sections are maintained in registration upon said pins.
 2. Theapparatus of claim 1, wherein said cut off means further includes:firstmeans for precutting areas of the insulating strip so that adjacentsections of the strip are co-joined by narrow non-cut areas; secondmeans down stream from said first means for affixing length of adhesivetape over the precut areas so that adjacent sections are furtherco-joined by said tape; and third means downstream from said secondmeans for severing the non-cut areas between the sections wherebyadjacent sections are co-joined by said tape.
 3. The apparatus of claim1 wherein said registration means includes articulated links having alength and a width sufficient to support an insulation section and themetal strip thereon and wherein said links contain said pins.
 4. Theapparatus of claim 3, wherein each link further includes:a platform forcarrying a section; a plate situated within said link that is spacedapart from the platform and movable therewith along the path of travel;and said pins protruding from said plate through said platform.
 5. Theapparatus of claim 4, wherein said platform and said plate are removablymounted upon said link.
 6. The apparatus of claim 1, wherein saidbonding means for attaching the insulation sections to the metal stripincludes holddown means for holding the sections and said strip incontact, an adhesive means, and heating means for heating the contactarea to activate said adhesive.
 7. The apparatus of claim 6, whereinsaid heating means is an induction heater.
 8. The apparatus of claim 6,wherein said holddown means further includes an endless chain for movinga series of press plates into contact with the registered insulationsection and the metal strip along said path of travel so that the stripand the sections are urged into contact by the press plates and saidheating means includes opposed heat inductors, one of which is mountedadjacent said conveyor and the other adjacent the endless chain.
 9. Theapparatus of claim 8, wherein each press plate includes a metal platethat rides in contact with the metal strips during bonding to diffuseheat.